JPH0894337A - Bottle inspection method and device - Google Patents

Abstract

(57) [Summary] [Purpose] To provide a bottle orientation inspection method and device that is easy to set and does not cause misjudgment due to other defects in the bottle. [Structure] A transparent bottle 1 having an uneven pattern 2 on one surface is illuminated by a surface light source 4 from a close range. If the unevenness pattern 2 is on the opposite side of the surface light source 4, a light beam is refracted at the edge portion of the unevenness pattern 2 so that a dark part of a certain pattern is generated.
This is captured by the camera 7 and processed by the image processing circuit 10 to determine the bottle orientation.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bottle orientation inspection method and apparatus used for aligning a transparent bottle or the like having a concavo-convex pattern on one surface in a fixed orientation.

[0002]

2. Description of the Related Art Some glass bottles for Western sake have a concavo-convex pattern such as engraving on one side and a smooth label side on the other side. Such bottles need to be aligned in a certain direction on the conveyor.

One of the conventional bottle orientation inspection methods for this purpose is to arrange a reflective photoelectric sensor 51 on the side of the conveyor 50 as shown in FIG.
This is a method of detecting 52 by reflected light, counting the number of pulses of the reflected light, and inspecting the front and back of the bottle according to its size.

Another conventional bottle orientation inspection method is the method described in Japanese Patent Application Laid-Open No. 58-216909. This method is shown in FIG.
This is a method of inspecting the front and back of the bottle by irradiating the bottle with one light beam from the light source and whether the light beam refracted by the irregularities 52 on the surface of the bottle is received by the photoelectric sensor 54.

However, in both the reflection type and transmission type methods described above, the set angle between the bottle surface suitable for detection and the sensor and the detection distance are limited to an extremely narrow range.
There is a problem that setting of the photoelectric sensors 51 and 54 is very difficult and there is no choice but to rely on an expert's setting skill. In particular, in the bottle manufacturing process, a large number of molds are used to manufacture bottles.Therefore, the degree of bulging of the unevenness of the bottles may differ slightly depending on the mold, and it is not possible to make common settings for bottles molded by any mold. It's not easy. Moreover, such adjustments must be made every time production is performed and every time a die is changed.

Further, in any of the above-mentioned reflection type and transmission type methods, since light rays are reflected or refracted by wrinkles, chills, dirt, and bubbles inside the bottle, the photoelectric sensor is The reflected light or the refracted light due to may be detected to make an erroneous determination. For this reason,
Even if the setting was done correctly, the conventional method using the photoelectric sensor could not reduce the erroneous judgment rate to 0.3% or less.

In particular, in the case of the transmission type shown in FIG. 14, since the light beam passes through both the front surface and the back surface of the bottle, if there is a character or the like on the opposite surface of the uneven portion, it may cause an erroneous determination. . For this reason, it was necessary to find an inspection area that was not affected by the opposite side, and some bottles could not inspect the front and back with this method.

[0008]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems of the prior art, is easy to set, is free from misjudgment due to other defects in bottles, and has an extremely limited inspection area. It was made to provide a bottle-free inspection method and device.

[0009]

The bottle orientation inspection method of the present invention is produced by illuminating a transparent bottle having an uneven pattern on one surface with a surface light source from a close distance and refracting a light beam at the edge of the uneven pattern. It is characterized in that whether or not the uneven pattern is on the surface light source side is determined by capturing a dark portion of a fixed pattern with a camera. In addition, the bottle orientation inspection apparatus of the present invention is provided with a surface light source for irradiating the bottle surface from a close range with a mask provided around one side of the conveyor through which a transparent bottle having an uneven pattern passes, and the opposite side of the conveyor. It is characterized in that a camera connected to an image processing circuit for recognizing a dark portion of a fixed pattern generated by refraction of a light ray at the edge portion of the uneven pattern is arranged on the side.

[0010]

In the present invention, a transparent bottle having an uneven pattern on one surface is illuminated from a close range by a surface light source having a mask around it. At this time, if the uneven pattern is on the side opposite to the surface light source, the light is refracted at the edge portion of the uneven pattern to generate a dark part of a certain pattern, and the camera can capture the dark part. However, if the uneven pattern is on the side of the surface light source, the rays of light wrap around and the camera cannot capture the dark part of a certain pattern.

Since the front and back of the bottle are inspected according to the above principle, it is not necessary to strictly set the surface light source and the camera in accordance with the uneven pattern. Moreover, since the pattern of the dark part is a fixed pattern determined by the uneven pattern, wrinkles,
Unaffected by defects such as chills and stains.
Moreover, even if there are irregularities such as characters on the surface light source side, there is no effect, so the inspection area is not limited. As a result, the erroneous determination rate, which is easy to set and cannot be reduced to 0.3% or less by the conventional method, can be reduced to 0.01% or less according to the present invention.

[0012]

The present invention will be described below in more detail with reference to the illustrated embodiments. FIG. 1 is a front view showing the apparatus of the embodiment, and FIG.
Is a plan view thereof. In these figures, 1 is a transparent bottle having an uneven pattern 2 on one side, and 3 is a conveyor for carrying the bottle 1. In this embodiment, the bottle 1 is assumed to be aligned in either the front or back direction by utilizing the outer shape in the previous stage, and is not the sideways one. A surface light source 4, an orientation sheet 5, and a mask 6 are provided on one side of the conveyor 3, and the bottle 1 passing on the conveyor 3 is illuminated from a close range as described later. A camera 7 is installed on the opposite side of the conveyor 3 and photographs the bottle 1 illuminated from behind by the surface light source 4. Reference numeral 8 is a photoelectric sensor to which a time delay function is added to synchronize the image pickup of the bottle 1, and 9 is a dark box which covers the whole.

Any surface light source 4 can be used as long as it can obtain a uniform surface illuminance. The orientation sheet 5 is for limiting the irradiation direction of the light from the surface light source 4, and a prism sheet or a perfect diffusion plate described later is used. The mask 6 is a shielding plate for determining the size of the area through which the light from the surface light source 4 transmits the bottle 1, and it is preferable that the size can be changed vertically and horizontally.

FIG. 3 is a diagram schematically explaining the inspection principle of the present invention. First, the bottle 1 is in the direction shown in the upper part of Fig. 3,
When the uneven pattern 2 is on the side opposite to the surface light source 4, the substantially parallel light rays emitted from the surface light source 4 pass through the inside of the transparent bottle 1 and are refracted in the uneven pattern 2 as shown in the figure.
As a result, a dark part where light does not enter from any direction occurs in a part of the image of the camera 7. On the other hand, when the bottle 1 is in the direction shown in the lower part of FIG. 3 and the concave / convex pattern 2 is on the side of the surface light source 4, a part of the substantially parallel light rays emitted from the surface light source 4 is the concave / convex pattern 2. Refraction by and does not produce a dark portion in the image of the camera 7. This effect is basically caused by the difference in the distance between the uneven pattern 2 and the surface light source 4, which will be described in more detail below.

FIG. 4 is an enlarged sectional view of a portion of the uneven pattern 2 on the bottle surface. As shown in this figure, the angle (obliquity) of the slope of the edge portion of the concavo-convex pattern 2 is x, and the angle made by the ray refracted by the slope of this edge and entering the camera 7 with respect to the normal to the slope is Let θ ₁ and θ ₂ , respectively. in this case,
The angle (incident angle) formed by the light ray with respect to the straight line connecting the surface light source 4 and the camera 7 is θ ₁ −x from a simple calculation. In this way, the incident angle θ ₁ -x of the light beam entering the camera 7 changes depending on the slope x of the uneven pattern 2. Here, if the refractive index of bottle glass is set to 1.5, the curve shown in Fig. 5 is obtained.

In the graph of FIG. 5, the slope x is plotted on the horizontal axis,
The vertical axis represents the incident angle of a light beam that is refracted by the surface of the inclination x and enters the camera 7. In the case of a glass bottle, the slope x of the edge of the uneven pattern 2 is 40 ° at the maximum, and in that case as well, the slope x actually includes a portion from 0 ° to a portion of 40 ° continuously. Therefore, as can be seen from the graph of FIG. 5, if the bottle 1 is illuminated with a light ray that uniformly contains components having an incident angle of 50 ° or less, the uneven pattern 2 cannot be captured by the camera 7 as a dark part. On the contrary, if the maximum value of the incident angle is made small (for example, if the maximum value of the incident angle is 20 ° even though the maximum gradient x is 40 °), it is refracted at a part of the slope of the uneven pattern 2. The rays of light do not enter the camera 7 and are recognized by the camera 7 as a clear dark area.

In order to secure the above effects, it is preferable to use the orientation sheet 5 which limits the irradiation direction of the light from the surface light source 4. 6A and 6B show the alignment characteristics of various alignment sheets. A shows a perfect diffusion plate in which light is uniformly diffused in each direction, and B shows a corrugated prism plate with a large amount of light diffusion in the normal direction. , C indicate triangular prism plates in which light is diffused more in the normal direction. In the present invention, a B or C prism orientation sheet 5 containing a large amount of necessary components is used. In particular, it is preferable to use the type B for inspecting a bottle having a sculpture, a molding, a chan or the like.
Moreover, a Fresnel lens sheet or a lenticular lens sheet may be used as the orientation sheet in order to obtain only the necessary diffused light component.

Further, in order to obtain the above-mentioned effects, the mask 6 is used in the present invention, and the size of the area through which the light from the surface light source 4 transmits the bottle 1 is determined. 7 and 8 show the mask 6
7A and 7B show a state in which the uneven pattern 2 is on the opposite side of the surface light source 4, and FIG. 8 shows a state in which the uneven pattern 2 is on the surface light source 4 side. The incident angle α shown in FIG. 7 is about 5 to 20 °, and β shown in FIG. 8 is about 35 to 60 °.
If the mask 6 is set so as to achieve the above-mentioned effects of the present invention can be obtained.

As shown in the graph of FIG. 5, if the slope x of the concave-convex pattern 2 of the bottle 1 exceeds 42 °, even if the incident angle β of the light beam is 35 to 60 °, it is completely dark. Cannot be extinguished. In this case, if the camera 7 is set to be slightly inclined, the position of the dark portion is deviated between the case where the concave-convex pattern 2 is on the camera side and the case where the concave-convex pattern 2 is on the opposite side. The front and back of can be determined. FIG. 9 is a diagram conceptually showing the screen of the camera 7. The lower part shows the case where the camera 7 is installed horizontally, showing how the dark part appears clearly or becomes almost invisible depending on the orientation of the bottle. There is. The upper row shows the case where the camera 7 is installed diagonally, and the darkness (thickness) depends on the orientation of the bottle.
Not only changes, but also the position changes.

The camera 7 is an image processing circuit 10 shown in FIG.
It is connected to the. The output of the camera 7 is first A / D converted, and the image pickup screen (see FIG. 11) is stored in the memory. Next, the inspection line is mapped on this memory. The inspection line means the shape of a dark portion of a constant pattern which is generated because the shape of the uneven pattern 2 is known in advance depending on the type of bottle. Then, the number of pixels of the dark portion in the mapped inspection line is counted, and the front and back of the bottle 1 are determined depending on whether or not the dark portion of the image in the inspection line is the required predetermined number. In this way, the image processing circuit 10 has the ability to recognize a dark portion of a certain pattern, and therefore wrinkles, chills,
There is no mistake in the judgment due to dirt or bubbles inside the bottle.

FIG. 12 shows an example in which the bottle orientation inspection apparatus of the present invention is incorporated in an actual conveyor line, and a bottle reversing mechanism 20 consisting of a pair of conveyors is provided at the subsequent stage of the bottle orientation inspection apparatus. . This is for inverting the bottle 1 according to the output of the image processing circuit 10 of the present invention so that the bottle 1 is aligned in a certain direction. The bottle orientation inspection device of the present invention is further provided at the subsequent stage, and this is for confirming that all the orientations of the bottle 1 are aligned. If a bottle 1 that is not aligned is found, the removing mechanism 21 blows the bottle 1 off the conveyor.

[0022]

As described above, according to the bottle orientation inspection method and apparatus of the present invention, there is no need for delicate setting as in the prior art. In addition, there is no erroneous determination due to defects such as wrinkles, chills, stains, and bubbles, and even if there are irregularities such as characters on the back surface, there is almost no effect, so the inspection area is not extremely limited. As a result, according to the present invention, the misjudgment rate for bottles can be significantly reduced from the conventional 0.3% to 0.01% or less.

[Brief description of drawings]

FIG. 1 is a front view showing an embodiment of the present invention.

FIG. 2 is a plan view showing an embodiment of the present invention.

FIG. 3 is a plan view schematically explaining the inspection principle of the present invention.

FIG. 4 is an enlarged view of an uneven pattern.

FIG. 5 is a graph showing a relationship between a slope and an incident angle of a light beam for eliminating a dark portion due to the slope.

FIG. 6 is an explanatory diagram illustrating the characteristics of an orientation sheet.

FIG. 7 is a plan view illustrating an effect of a mask.

FIG. 8 is a plan view illustrating the effect of the mask.

FIG. 9 is a diagram showing an image of a camera.

FIG. 10 is a block diagram showing an image processing circuit.

FIG. 11 is an explanatory diagram showing a relationship among an image, an imaging screen, and an inspection line.

FIG. 12 is a plan view showing a usage state on an actual line.

FIG. 13 is a plan view showing a conventional method.

FIG. 14 is a front view showing another conventional method.

[Explanation of symbols]

 1 Bottle 2 Concavo-convex pattern 3 Conveyor 4 Surface light source 5 Alignment sheet 6 Mask 7 Camera 8 Photoelectric sensor 9 Dark box 10 Image processing circuit 20 Bottle reversing mechanism 21 Exclusion mechanism

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location G06T 7/00 7/60

Claims (2)

[Claims] 1. A concavo-convex pattern is obtained by illuminating a transparent bottle having a concavo-convex pattern on one surface from a close distance with a surface light source and capturing a dark portion of a certain pattern caused by refraction of light rays at the edge of the concavo-convex pattern with a camera. The method for inspecting bottles is characterized by determining whether or not there is a surface light source side. 2. A surface light source for illuminating the surface of a bottle from a short distance is provided on one side of a conveyor through which a transparent bottle having an uneven pattern passes, and an uneven pattern is provided on the opposite side of the conveyor. An apparatus for inspecting bottles, characterized in that a camera connected to an image processing circuit for recognizing a dark portion having a certain pattern caused by refraction of light rays at the edge portion of the bottle.